Hydrogen-bonded interpenetrating

Porosity may be generated, for instance, either by using awkwardly shaped molecules like 425 or by creating a net with large cages or channels (avoiding interpenetration)due to hydrogen bonds or coordination. In this way three-(3D) or two-dimensional (2D) nets are created which can host smaller molecules. Few... 

Because LHC is a complex of interpenetrating polymers, hydrogen bonds and ester cross-links can reestablish themselves unless further processing occurs promptly. Therefore, in practice, this disruption of the LHC phase may not be distinguishable from the subsequent stages. 

Wuest et al. have also prepared a related tetrahedral tecton 8.63, which also produces a diamondoid polymeric framework. In this case, the solid-state network is seven-fold interpenetrated, with one diamondoid lattice filling much of the large cavities in those adjacent. It is possible that the interpenetration in this instance is a result of the self-complementary nature of the host, which contains an equal number of hydrogen bond donor and acceptor sites. However, even in this case small cavities exist, which are filled by two molecules of butyric acid per host formula unit. The formation of these kinds of framework materials opens entirely new possibilities for tailor-made porous materials with very large cavities, although it is unlikely that purely organic frameworks will ever rival aluminosilicate-based materials for sheer mechanical strength. 

Figure 9.36 ID—>1D parallel interpenetration of hydrogen bonded strands of 4,4 -trimethylenedipyridine 9.12 and 4,4 -sulfonyldiphenol 9.13.

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